Articulators are well known dental devices which attempt to replicate the movement of the lower jaw relative to the upper jaw about the Temporomandibular Joint (TMJ) in a patient-specific manner. Typically, plaster models of the patient's upper and lower teeth arches are mounted to the articulator with respect to its hinge axis in a manner simulating that of the real teeth arches with respect to the patient's TMJ joint. Traditionally, physical impressions of the dental arches are provided, which are then used for casting the plaster models. In addition, a bite impression is obtained with a wax bite plate, which records the relative positions of the upper and lower arches.
A mechanical facebow with a bite fork is often used for obtaining patient-specific measurements which are then used to set up the plaster model in a particular articulator. In particular, the spatial orientation of the patient's maxillary arch with respect to the ear canals is duplicated by the facebow. The facebow is engaged to the ear canals via an ear canal insertion portion. Then, a bite fork with impression material is brought into engagement with the maxillary teeth, and a jig connects the bite fork via its arm to the facebow. The facebow and bite fork combination are then mechanically rigidly coupled to the articulator, such that the ear canal insertion portions are in the corresponding alignment with the pivot axis of the articulator. The plaster models are mounted to the articulator so as to engage and thus match the position of the bite fork, and plaster filling is provided between each plaster model and the respective articulator arm. However, this is a complicated and time consuming process, and which requires expert handling. Once the models are mounted, the facebow and bite fork can be removed.
The articulator mounted with the plaster models can be made use of for a large number of orthodontic, prosthodontic and other dental applications. For example, dental restoration procedures often make use of articulators to design and test prostheses before implantation in a patient.
By way of general background, U.S. Pat. No. 6,152,731 discloses a computer implemented method that includes providing a first set of digital data corresponding to an upper arch image of at least a portion of an upper dental arch of a patient, providing a second set of digital data corresponding to a lower arch image of at least a portion of a lower dental arch of the patient, providing bite alignment data representative of the spatial relationship between the upper dental arch and the lower dental arch of the patient, and aligning the upper and lower arch images relative to one another based on the bite alignment data until an aligned upper and lower arch image is attained. The aligned upper and lower arch images are moved towards each other until a first contact point is detected and at least one of the upper and lower arch images is moved relative to the other in one or more directions to a plurality of positions for determining optimal occlusion position of the lower and upper dental arches.